#include<bits/stdc++.h>
using namespace std;
#define ll long long

void solve() {
	int n;
	cin >> n;
	vector<int> a(n + 1);
	ll ans = 0;
	map<int, vector<int>> mp;
	for(int i = 1; i <= n; i++) {
		cin >> a[i];
		mp[i - a[i]].push_back(a[i]);
	}
	for(auto[i, e]: mp) {
		sort(e.begin(), e.end(), greater<>());
		// for(auto u: e) {
		// 	cout << u << ' ';
		// }
		// cout << endl;
		for(int i = 0; i + 1 < e.size(); i += 2) {
			if(e[i] + e[i + 1] > 0) {
				ans += e[i] + e[i + 1];
			}
		}
	}
	cout << ans << endl;
}

int main() {
	int t = 1;
	cin >> t;
	while(t--) {
		solve();
	}
	return 0;
}